Shabbat Prayers: Mussaf: “Tikanta”
Shabbat Mussaf corresponds to Yosef ha-Tzaddik (Pri Tzaddik, Succot, #22). Yosef is the meeting point between the Upper and Lower Worlds. He brings down Shefa, Abundance, from Heaven, and takes our efforts on this world and elevates them upward to Heaven. This is why the Mussaf is composed with a backward Aleph-Bet.
Until this point of Shabbat our efforts have been to grab all the Abundance from Heaven. At this point, we redirect our efforts to take that abundance, use it to transform all we do here, even our eating and drinking, so that they will be so empowered that they will stir the Heavens and nurture further and expansive blessings to shower down on us.